3 Answer:
A step-up transformer is used in
a. tape players
b. calculators
c. doorbells
d. television sets
4 Answer:
The best core for an electromagnet is
a. alnico
b. iron
c. aluminum
d. magnetite
5 Answer:
Which of the following will "not" strengthen an electromagnet?
a. increasing the number of loops of wire around the core
b. increasing the current flow
c. decreasing the voltage
d. all of these
6 Answer:
In order for a motor to run off direct current, it must contain a
a. galvanometer
b. U-shaped magnet
c. primary coil
d. commutator
7 Answer:
The phenomenon in which a current is produced by a changing magnetic
field is called electromagnetic
a. conduction
b. transformation
c. induction
d. generation
8 Answer:
Alternating current in the United States has a frequency of
a. 30 hertz
b. 60 hertz
c. 120 hertz
d. 240 hertz
9 Answer:
Almost all of the electricity that people use is produced by
a. generators
b. motors
c. batteries
d. transformers
10 Answer:
A step-down transformer is used in
a. doorbells
b. X-ray machines
c. fluorescent lights
d. television sets
